Conveyer belt structure



Sept. 1942- I R. H. SHARPE 2,295,133

CONVEYER BELT STRUCTURE Filed July 22, 1940 'E 'IE-E INVENTOR. R055?! H. SHA/PPB Patented Sept. 8, 1942 UNITED STATES E ATENT OFFECIE CONVEYER BELT STRUCTURE;

Robert H. Sharpe, akland, .C'alif..

Application July 22, 1940, Serial No. 346,702

4 Claims.

The invention relates to a conveyer belt structure and particularly to one which is especially capable for use for a draper in a harvester. More particularly, the invention relates to this type of structure in which the belt has provided thereon a marginal band or strip which serves as a general reenforcement for the structure and as a means for efiecting an improved gripping medium with the pulley or roller about which the belt travels.

An object of the invention is to provide means in connection with the marginal strips or bands which will prevent any sharp fiexure inthe belt along the inner edge of the bands, due to the load on the belt when the belt is bent around the pulley.

Another object of the invention is to provide a means of the character described which is incorporated therein as an integral part of the marginal band.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred form of the invention which is illustrated in the drawing accompanying and forming part of the specification. It is to be understood, however, that variations in the showing made by the said drawing and description may be adopted within the scope of the invention as set forth in the claims.

Referring to said drawing:

Figure 1 is a fragmentary transverse sectional view of a draper belt constructed in accordance with my invention.

Figure 2 is a bottom view of the belt shown in Figure 1.

Figure 3 is a sectional view similar to Figure l but showing a modified construction.

Figure 4 is a cross-sectional view of a further modified form of the invention.

As above explained, draper belts have heretofore been formed with marginal bands for the purpose set forth. Usually these bands have been formed by folding the edge portion of the belt over the body portion thereon and inserting between such portions a breaker strip which consists of one or more layers of belt stock which is vulcanized to the belt portions. The inner edge of the layers terminates flush with the inner edge of the folded portion of the belt. The slats or cleats on the draper belt are usually positioned on the side opposite the one on which the marginal strip is built, and the marginal strip is arranged to lie on the inner sideof the belt so as to directly engage the surface of the pulleys around which the draper belt travels. As will be clear, during the operation of the draper, 'the load upon the belt will exert a pull on the body portion of the belt so that as the belt is bent around the pulley or roller, a sharp buckling or flexure will occur in the belt at the inner edge of the bands. This tendency to buckle is brought about by the fact that the portion of the belt at the inner edge of the band is pulled down to a smaller radius than the adjacent band portion. This continual flexing of the belt portion imposes such a strain along the inner edge of the band that such portion prematurely wears so as to soon render the belt unfit for use. With my invention the marginal band, instead of being abruptly terminated at the inner edge, is caused to extend inwardly for a certain distance at a gradually decreasing thickness. The portion of the belt adjacent the band will be permitted to flex only on a wide predetermined curve and at the same time such portion will be greatly reenforced so that there will be no danger. of the aforesaid break or premature wear of the belt.

The belt 3 is formed of the usual belting material, such as heavy canvas, of the appropriate size and as here shown, is constructed of woven fabric treated with rubber, and such as is commonly known as draper stock. Normally both edges of the belt are arranged to be made the same, and as will be clear from Figure l, a portion 4 of the material at the edge is folded over the adjacent body portion 5, between which is arranged to be contained what may be called the breaker strip 6. The latter is conveniently formed of the same material as the belt and consists. as here shown, of a section of such material folded upon itself so as to provide a double layer and inserted between the belt portions 4 and 5 aforesaid with the connected edge of the layers lying adjacent the connected edge of said portions.

Both of the free edges of the breaker strip layers protrude from the free edge of the band portion 4, and preferably with the layer 1 which is adjacent the belt body, extended further toward the center of the belt than the layer 3 which is adjacent the portion 4. The extent of protrusion of the breaker strip from the band portion is quite appreciable and as here shown, the protrusion of the layer 1 is more than onehalf the width of the portion 4. The edge of the layer 8 preferably extends to midway of the space between the inner portion of the band and the outer edge of layer 1. The exposed ends of the layers are beveled over a wide area so that the decrease in thickness of the belt from the portion 4 is brought about not only through! the successive termination of the breaker strip portions but by the gradual reduction in the thickness of the layers.

The layers of the breaker strip are vulcanized together and to the portions 4 and 5 so that the band proper and the extension provided by the breaker strip addition, form an integral part of the belt and control its strength and flexibility.

With the belt formed in the manner described, as the belt is bent in conformity with a pulley, practically all portions of the belt adjacent the marginal band will engage and be supported upon the pulley, thereby preventing transverse flexure of the belt except in a smooth curve of large radius. It will also be evident that with such marginal band extension any flexing concentration along the inner edge of the marginal band due to the continuous reverse flexing of the belt in the operation of the draper, will be prevented, since the resistance to flexing in the portion of the belt adjacent the band decreases gradually over a relatively wide area.

In Figure 3 I have shown a somewhat modified form of th structure. In this embodiment the marginal band extension is simply formed of a triangular shaped fillet [2 formed of rubber or the like and positioned with its edge l3 of greater dimension at the inner edge of the strip. The fillet I2 is preferably held in position by vulcanizing the same to the belt.

In Figure 4 I have shown a still further modified form. In this arrangement, the flexing of the belt portion contiguous to the marginal band is resisted by a resilient metal strip M of preferably uniform thickness, the strip serving to prevent the flexing of the belt by the resistance of the strip to flexing rather than by contact of the belt on the pulley.

As will be clear from the drawing, the strip I 4 is partially inserted and held in place between the body portion 5 of the belt and th breaker strip contained between such portion and the portion 4. Preferably the strip [4 extends inwardly beyond the inner edge of the marginal band toward the center line of the belt about the same distance as the fillet [2 of Figure 3.

I claim:

1. In a belt of the character described, a body having one side smooth and unobstructed and a marginal band on the reverse side thereof, and a reenforcing strip coextensive longitudinally with said band and extending transversely inwardly over the body from between the band and body in substantially gradually decreasing thickness.

2. In a belt of the character described, a body having one side smooth and unobstructed from one edge to the other, a marginal member positioned wholly upon the other side of the body and defining a space therebetween, and a breaker strip vulcanized between said marginal portion and opposed portion of the body and comprising a plurality of layers of flexible material extending in part inwardly over the belt body from said marginal portion, said layers in their order from the marginal portion to the opposed body portion successively terminating at greater distances from the inner edge of the marginal portion to thereby provide an exposed reverse crown on the layered side of the belt.

3. A belt in accordance with claim 4 characterized by the exposed portions of the layers being beveled.

4. In a belt of the character described, a body having an unobstructed exposed planar surface on one side from one edge of the body to the other and provided on the reverse side with marginal members with decreasing thicknesses from the outer edge inwardly and defining with said reverse side an exposed shallow recess on such side of the body.

- ROBERT H. SHARPE. 

